-#endif])
- AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
- [ac_cv_safe_to_define___extensions__],
- [AC_COMPILE_IFELSE(
- [AC_LANG_PROGRAM([
- #define __EXTENSIONS__ 1
- AC_INCLUDES_DEFAULT])],
- [ac_cv_safe_to_define___extensions__=yes],
- [ac_cv_safe_to_define___extensions__=no])])
- test $ac_cv_safe_to_define___extensions__ = yes &&
- AC_DEFINE([__EXTENSIONS__])
- AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
-])])
+#endif
+/* Enable extensions on HP NonStop. */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable general extensions on Solaris. */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+])
+ AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
+ [ac_cv_safe_to_define___extensions__],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[
+# define __EXTENSIONS__ 1
+ ]AC_INCLUDES_DEFAULT])],
+ [ac_cv_safe_to_define___extensions__=yes],
+ [ac_cv_safe_to_define___extensions__=no])])
+ test $ac_cv_safe_to_define___extensions__ = yes &&
+ AC_DEFINE([__EXTENSIONS__])
+ AC_DEFINE([_ALL_SOURCE])
+ AC_DEFINE([_GNU_SOURCE])
+ AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
+ AC_DEFINE([_TANDEM_SOURCE])
+])# AC_USE_SYSTEM_EXTENSIONS
+
+# gl_USE_SYSTEM_EXTENSIONS
+# ------------------------
+# Enable extensions on systems that normally disable them,
+# typically due to standards-conformance issues.
+AC_DEFUN([gl_USE_SYSTEM_EXTENSIONS],
+ [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])])